Ti-6Al-4V钛合金的疲劳裂纹扩展规律

针对熔模铸造Ti-6Al-4V钛合金的等幅疲劳裂纹扩展速率和疲劳裂纹扩展门槛值进行了研究。结果表明：该钛合金CT试样的疲劳裂纹扩展门槛值高于CCT试样的疲劳裂纹扩展门槛值,同一类试样的疲劳裂纹扩展门槛值随着应力比的增加呈下降趋势;疲劳裂纹扩展速率随着平均应力的增加以及应力水平的增加而增大;根据疲劳裂纹扩展试验数据拟合了Ti-6Al-4V钛合金Paris方程和Walker方程中的相关材料参数,以为材料的使用寿命评估及损伤容限设计提供参考。

igue Crack Propagation Rules of Ti-6Al-4V Titanium Alloy

The fatigue crack propagation rate under constant amplitude loading and the fatigue crack propagation threshold value of Ti-6Al-4V titanium alloy were studied by tests.The results indicate that the fatigue crack propagation threshold values of CT specimens were higher than that of CCT specimens for the same material,and the fatigue crack propagation threshold values of the same kind of specimens decreased linearly with the increase of the test stress ratio.The change rules of fatigue crack propagation rate increased with the increase of average stress and stress level were gained.The material parameters of the Paris and Walker equations were derived from the test data for Ti-6Al-4V titanium alloy.The research results could provide reference for assessment of the material life and damage tolerance design.